Magnetic resonance brown fat activity imaging method, system and equipment and storage medium

Abstract

The invention discloses a magnetic resonance brown fat activity imaging method, system and equipment and a storage medium. The method comprises the following steps: acquiring a chemical exchange saturation transfer image of a shoulder and neck region of a human body; performing normalization processing on the acquired chemical exchange saturation transfer image to obtain an original Z-spectrum image, performing primary three-pool Lorentz curve fitting on the original Z-spectrum image, finding out the position of a water peak, and correcting the main magnetic field nonuniformity of the original Z-spectrum image; and carrying out two-pool Lorentz curve fitting on the Z-spectrum image after main magnetic field non-uniformity correction again, extracting a creatine signal contained in the Z-spectrum image, and taking the creatine signal as an image quantitative index for reflecting the brown fat activity level to realize brown fat activity imaging. The method is non-invasive, non-radiative and low in cost, can be used in women and children, and is suitable for large-queue and repeated observation research.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic resonance imaging, and in particular relates to a magnetic resonance brown fat activity imaging method, system, equipment and storage medium. Background Art

[0003] In order to further understand the role of brown fat in the human body and analyze its relationship with various metabolic diseases, it is particularly important to directly quantify the activity level of brown fat in the body. The currently recognized method for quantifying brown fat activity is 18 F-FDG PET / CT imaging method, which assesses the activity level of brown fat by detecting the uptake of glucose by brown fat. However, this method is expensive, involves ionizing radiation, and is not suitable for use in women and children, as well as for large cohort and repeated observational studies.

[0004] In addition to glucose, creatine also plays a key role in brown fat thermogenesis. Creatine is closely related to mitochondrial metabolism and plays an important role in mitochondrial oxidative phosphorylation. Studies have shown that reduced creatine levels in adipose tissue impair adipocyte thermogenesis and enhance diet-induced obesity. On the other hand, under conditions that restrict adipocyte creatine abundance, such as genetic adipocyte creatine reduction or intermittent fasting, creatine supplementation can increase whole-body energy expenditure in mice. These studies have demonstrated from different aspects the possibility of creatine as a biomarker of brown fat metabolic function and a potential diagnostic and therapeutic evaluation tool for metabolic diseases.

[0005] Chemical exchange saturation transfer imaging is an emerging non-invasive endogenous metabolic imaging technology, which is mainly used to detect metabolites that can exchange protons with water. By collecting chemical exchange saturation transfer weighted images under different saturation frequency offsets, a Z spectrum is generated. Based on the metabolite abundance, exchange rate and frequency offset of exchanged protons expressed in tissues, chemical exchange saturation transfer imaging can perform non-invasive imaging of metabolites such as creatine, protein, glycogen, and glutamate. In addition, fat signals have always been considered artifacts in chemical exchange saturation transfer imaging, and researchers have been working hard to suppress or remove them. In the present invention, an opposite innovative strategy is adopted, and fat and creatine signals are retained simultaneously in chemical exchange saturation transfer imaging, realizing the combination of fat content and adipocyte metabolic function imaging.

[0006] In summary, in order to monitor the activity level of human brown fat more economically and safely, and to better diagnose and evaluate obesity-related metabolic diseases, the present invention describes a magnetic resonance brown fat activity imaging method. Through this method, a non-invasive and radiation-free brown fat metabolic activity imaging detection method can be provided for clinical use. Summary of the invention

[0007] The main purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, and to provide a magnetic resonance brown fat activity imaging method, system, device and storage medium. The method is based on the detection ability of chemical exchange saturation transfer imaging for creatine signals, combined with a piecewise Lorentz curve fitting process, to achieve non-invasive and radiation-free in vivo quantitative detection of brown fat activity.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention discloses a magnetic resonance brown fat activity imaging method and application, comprising the following steps:

[0010] A chemical exchange saturation transfer image of the human shoulder and neck area is collected; the collected chemical exchange saturation transfer image is normalized to obtain an original Z spectrum image, the original Z spectrum image is initially fitted with a three-pool Lorentz curve to find the location of the water peak, and the main magnetic field inhomogeneity of the original Z spectrum image is corrected; the Z spectrum image after the main magnetic field inhomogeneity is corrected is again fitted with a two-pool Lorentz curve to extract the creatine signal contained in the Z spectrum image, and the creatine signal is used as an image quantification indicator reflecting the activity level of brown fat to achieve brown fat activity imaging.

[0011] As a preferred technical solution, the specific operation of chemical exchange saturation transfer image data acquisition in the image acquisition module is as follows: a chemical exchange saturation transfer magnetic resonance sequence is used to acquire multiple radio frequency pulse saturation images M at different frequency offsets of relative water protons in the magnetic resonance imaging system. z , and an additional non-saturated reference image M0.

[0012] Among them, for chemical exchange saturation transfer magnetic resonance imaging, the applied pre-saturation radio frequency pulse waveform is a single continuous Gaussian pulse, but is not limited to a Gaussian pulse. In order to ensure that sufficient chemical exchange saturation transfer effects can be observed, the applied pre-saturation radio frequency pulse time should be relatively long, about ≥2s; but too long pre-saturation radio frequency pulse duration will seriously increase the bandwidth of the water signal peak, so the applied pre-saturation radio frequency pulse time should be ≤3s. Considering that the present invention is mainly applied to adipose tissue imaging, and the chemical frequency offsets of water and fat signals in magnetic resonance spectroscopy imaging are 4.7ppm and 1.3ppm respectively, the frequency offset interval of the two substances is about 3.4ppm, that is, the relative water proton frequency offsets of water and fat signals are 0ppm and -3.4ppm respectively. Therefore, in the magnetic resonance brown fat activity imaging method and application, in order to better and accurately extract the metabolite content level related to fat activity, the relative water proton resonance frequency offset range collected by chemical exchange saturation transfer magnetic resonance imaging should be at least greater than ±5.0ppm.

[0013] As a preferred technical solution, the specific operation of the main magnetic field inhomogeneity correction module is as follows: multiple radio frequency pulse saturation images M under different frequency offsets in the collected chemical exchange saturation transfer image data are z The non-saturated reference image M0 is normalized to obtain the original Z spectrum (Z = 1-M z / M0).

[0014] The original Z spectrum was fitted with a first three-pool Lorentz curve, which included the direct saturated water pool, the methylene fat pool, and the asymmetric macromolecular proton pool.

[0015] The three-pool Lorentz curve fitting model is:

[0016]

[0017] Among them, i = 1 is the direct saturated water pool, i = 2 is the methylene fat pool, and i = 3 is the asymmetric macromolecular proton pool. Z(ω) is a number of L i (ω) The entire Z spectrum formed after superposition; L i (ω) is a signal peak with a peak value of A, a center frequency offset of ω0, a frequency offset of ω, and a peak half-width of lω.

[0018] The extracted direct saturated water signal and methylene fat signal are referred to as water signal W and fat signal F, respectively. According to the formula The proportion of fat signal in water and fat signal in a unit voxel is calculated to roughly estimate the fat content distribution map. The entire scanning field is traversed in pixels, and according to the results of the fat content distribution map, the fat tissue area (FF>20%) and the tissue area dominated by water signal (FF<20%) are distinguished with FF≥20% as the threshold. Different main magnetic field inhomogeneity correction treatments are performed on the fat tissue area and the tissue area dominated by water signal.

[0019] Among them, for the fat tissue area, first extract the highest peak and the second highest peak of the signal contained in the original Z spectrum, and confirm the order of appearance of the highest peak and the second highest peak according to the principle of gradually decreasing relative water proton frequency offset from left to right (that is, the X-axis of the Z spectrum is marked from +10.0ppm to -10.0ppm from left to right), and mark the signal peak closer to the left of the Z spectrum X-axis as water peak W, and the signal peak closer to the right of the Z spectrum X-axis as fat signal peak F. Then, the Z spectrum main magnetic field inhomogeneity correction is performed based on the relative water proton frequency offset a where the fat signal peak F is located, and all relative water proton frequency offsets in the original Z spectrum are corrected by an offset of -a-3.4, and the Z spectrum after the main magnetic field inhomogeneity correction can be obtained. Correspondingly, for the tissue area dominated by water signals, extract the maximum signal peak contained in the original Z spectrum, and the maximum signal peak is the water signal peak W. The relative water proton frequency offset b where the water signal peak W is located is set as the inhomogeneity offset of the main magnetic field, and all relative water proton frequency offsets in the original Z spectrum are corrected by an offset of -b to obtain the Z spectrum after the main magnetic field inhomogeneity correction.

[0020] As a preferred technical solution, the specific operation of the brown fat activity imaging of the image reconstruction module is as follows: record the water signal W, fat signal F and asymmetric macromolecular proton signal obtained by the first three-pool Lorentz curve fitting. Subtract the water signal W, fat signal F and asymmetric macromolecular proton signal mentioned above from the Z spectrum after the main magnetic field inhomogeneity correction to obtain the remaining Z spectrum. Perform a second two-pool Lorentz curve fitting on the remaining Z spectrum to fit the creatine signal and amide proton transfer signal contained in the remaining Z spectrum. Among them, the creatine signal is used as an imaging indicator to quantify the brown fat activity level.

[0021] The two-pool Lorentz curve fitting model is:

[0022]

[0023] Wherein, j=1 is the creatine signal pool, j=2 is the amide proton transfer signal pool. Z(ω) is the two L j (ω) The entire Z spectrum formed after superposition; L j (ω) is a signal peak with a peak value of A, a center frequency offset of ω0, a frequency offset of ω, and a peak half-width of lω.

[0024] As a preferred technical solution, the clinical application module observes the changes in brown fat activity of healthy volunteers before and after cold exposure as follows: The cold exposure experimental conditions are to apply a medical cold compress ice pack (6-10°C) to the shoulder and neck for 2 hours at a room temperature of 16-17°C, and avoid strenuous exercise during the period. The chemical exchange saturation transfer imaging data of the brown fat tissue of the shoulder and neck of healthy volunteers before and after cold exposure are collected to observe the effect of cold exposure on the activity of brown fat in the shoulder and neck of the human body. The contrast of the obtained creatine signal corresponds to the activity of brown fat in the shoulder and neck of the human body.

[0025] As a preferred technical solution, the relative water proton resonance frequency offset range of the saturated image acquired by the chemical exchange saturation transfer imaging data is from -10ppm to +10ppm, which must include -3.5ppm, 0ppm, +2.0ppm and +3.5ppm saturated images, plus a non-saturated image with a frequency offset of +300ppm. Preferably, the relative water proton frequency offset of the chemical exchange saturation transfer image collected by the Z spectrum is: +300ppm, ±10ppm, ±8ppm, ±6ppm, ±5.75ppm, ±5.5ppm, ±5.25ppm, ±5ppm, ±4.75ppm, ±4.5ppm, ±4.25ppm, ±4.0ppm, ±3.75ppm, ±3.5ppm, ±3.25ppm, ±3.0ppm, ±2.75ppm, ±2.5ppm, ±2.25ppm, ±2.0ppm, ±1.75ppm, ±1.5ppm, ±1.25ppm, ±1.0ppm, ±0.75ppm, ±0.5ppm, ±0.25ppm, and 0ppm. It is worth noting that the acquisition of chemical exchange saturation transfer imaging data is not limited to the relative water proton resonance frequency shift images included above. Smaller relative water proton resonance frequency shift image intervals help to extract more accurate brown fat activity-related creatine signals, but will increase the acquisition time of magnetic resonance imaging data and be more susceptible to motion artifacts.

[0026] In a second aspect, the present invention provides a magnetic resonance brown fat activity imaging system, which is applied to the magnetic resonance brown fat activity imaging method, and includes an image acquisition module, a main magnetic field inhomogeneity correction module and an image reconstruction module;

[0027] The image acquisition module is used to acquire chemical exchange saturation transfer images of the shoulder and neck area of ​​the human body;

[0028] The main magnetic field inhomogeneity correction module is used to normalize the collected chemical exchange saturation transfer image to obtain an original Z spectrum image, perform a first three-pool Lorentz curve fitting on the original Z spectrum image, find the location of the water peak, and correct the main magnetic field inhomogeneity of the original Z spectrum image;

[0029] The image reconstruction module is used to perform two-pool Lorentz curve fitting again on the Z spectrum image after the main magnetic field inhomogeneity correction, and extract the creatine signal contained in the Z spectrum image. The creatine signal is used as an image quantification index reflecting the brown fat activity level to achieve brown fat activity imaging.

[0030] In a third aspect, the present invention provides an electronic device, the electronic device comprising:

[0031] at least one processor; and,

[0032] a memory communicatively connected to the at least one processor; wherein,

[0033] The memory stores computer program instructions that can be executed by the at least one processor, and the computer program instructions are executed by the at least one processor to enable the at least one processor to perform the magnetic resonance brown fat activity imaging method.

[0034] In a fourth aspect, the present invention provides a computer-readable storage medium storing a program, which, when executed by a processor, implements the magnetic resonance brown fat activity imaging method.

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] (1) Existing methods for imaging brown fat activity ( 18 F-FDG PET / CT) by exogenous injection 18 F-FDG is used to detect the glucose uptake capacity of brown adipose tissue to reflect the activity of brown adipose tissue. 18 The F-FDG PET / CT method is expensive and emits ionizing radiation to the human body, which is not conducive to its promotion and use in clinical practice. The magnetic resonance brown fat activity imaging method proposed in the present invention is an endogenous imaging method that is non-invasive and radiation-free, low-cost, can be used in women and children, and is suitable for large cohorts and repeated observational studies.

[0037] (2) Existing magnetic resonance-based brown fat imaging methods mainly focus on the quantification of fat content and cannot detect information directly related to the activity level of brown adipose tissue, such as fat quantitative imaging technology based on Dixon water-fat separation. The magnetic resonance brown fat activity imaging method proposed in the present invention can directly reflect the activity level of brown adipose tissue by quantifying the creatine content inside the brown adipose tissue. At the same time, the invention can also obtain information on fat content, realizing the combination of fat content and fat metabolic activity imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 This is a schematic diagram of the process of a magnetic resonance brown fat activity imaging method according to an embodiment of the present invention;

[0040] Figure 2 The Z spectrum is formed by normalizing a plurality of chemical exchange saturation transfer weighted images with different frequency offsets according to an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of the first three-cell Lorentz curve fitting of an embodiment of the present invention, and a schematic diagram of the main magnetic field inhomogeneity correction;

[0042] Figure 4 This is a schematic diagram of the second two-pool Lorentz curve fitting in an embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of the superposition results of two Lorentz curve fittings according to an embodiment of the present invention;

[0044] Figure 6 This is a flow chart of a clinical human cold exposure experiment according to an embodiment of the present invention;

[0045] Figure 7 This is a comparison of the Z spectrum of brown adipose tissue before and after cold exposure in a clinical human body according to an embodiment of the present invention;

[0046] Figure 8 The change of creatine content level in brown adipose tissue of human body before and after cold exposure in clinical practice of the present invention;

[0047] Fig. 9 4 is a block diagram of a magnetic resonance brown fat activity imaging system according to an embodiment of the present invention.

[0048] Fig.10 4 is a structural diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0050] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0051] like Figure 1 As shown, the magnetic resonance brown fat activity imaging method of this embodiment includes the following steps:

[0052] S1. Collect chemical exchange saturation transfer images of the human shoulder and neck area.

[0053] Specifically, the chemical exchange saturation transfer magnetic resonance sequence in the magnetic resonance imaging device is used to scan and collect image data of the human shoulder and neck, and the image data obtained is as follows: Figure 2 shown.

[0054] Furthermore, a chemical exchange saturation transfer magnetic resonance sequence is used to acquire multiple radio frequency pulse saturation images M at different frequency offsets relative to water protons in a magnetic resonance imaging system. z , and an additional non-saturated reference image M0.

[0055] Among them, for chemical exchange saturation transfer magnetic resonance imaging, the applied pre-saturation radio frequency pulse waveform is a single continuous Gaussian pulse, but is not limited to a Gaussian pulse. In order to ensure that sufficient chemical exchange saturation transfer effects can be observed, the applied pre-saturation radio frequency pulse time should be relatively long, about ≥2s; but too long pre-saturation radio frequency pulse duration will seriously increase the bandwidth of the water signal peak, so the applied pre-saturation radio frequency pulse time should be ≤3s. Considering that the present invention is mainly applied to adipose tissue imaging, and the chemical frequency offsets of water and fat signals in magnetic resonance spectroscopy imaging are 4.7ppm and 1.3ppm respectively, the frequency offset interval of the two substances is about 3.4ppm, that is, the relative water proton frequency offsets of water and fat signals are 0ppm and -3.4ppm respectively. Therefore, in the magnetic resonance brown fat activity imaging method and application, in order to better and accurately extract the metabolite content level related to fat activity, the relative water proton resonance frequency offset range collected by chemical exchange saturation transfer magnetic resonance imaging should be at least greater than ±5.0ppm.

[0056] In a specific embodiment, the acquisition parameters of the chemical exchange saturation transfer image are as follows: a pre-saturation excitation pulse (pulse duration is about 2.0s to 3.0s, saturation pulse intensity is about 1.0μT) is applied before the fast spin echo sequence, and then multiple saturation images M at different frequency offsets are acquired. z(±10ppm, ±8ppm, ±6ppm, ±5.75ppm, ±5.5ppm, ±5.25ppm, ±5ppm, ±4.75ppm, ±4.5ppm, ±4.25ppm, ±4.0ppm, ±3.75ppm, ±3.5ppm, ±3.25ppm, ±3.0ppm, ±2.75ppm, ±2.5ppm, ±2.25ppm, ±2.0ppm, ±1.75ppm, ±1.5ppm, ±1.25ppm, ±1.0ppm, ±0.75ppm, ±0.5ppm, ±0.25ppm, and 0ppm.) and a non-saturated image M0 (+300ppm).

[0057] S2. Correction of main magnetic field inhomogeneity; the specific steps are:

[0058] S21, the saturation images M collected at all different frequency offsets in the collected chemical exchange saturation transfer image z The non-saturated reference image M0 is normalized to obtain the original Z spectrum (Z = 1-M z / M0). Perform the first three-cell Lorentz curve fitting on the original Z spectrum (such as Figure 3 The directly saturated water pool, methylene fat pool, and asymmetric macromolecular proton pool contained therein are fitted.

[0059] Furthermore, the model used for the three-pool Lorentz curve fitting is as follows:

[0060]

[0061] Among them, i = 1 is the direct saturated water pool, i = 2 is the methylene fat pool, and i = 3 is the asymmetric macromolecular proton pool; Z (ω) is a number of L i (ω) The entire Z spectrum formed after superposition; L i (ω) is a signal peak with a peak value of A, a center frequency offset of ω0, a frequency offset of ω, and a peak half-width of lω.

[0062] S22, extract the direct saturated water signal W and the methylene fat signal F; according to the formula (W and F are the peak values ​​of the extracted water and fat signals, respectively), calculate the proportion of fat signal in water and fat signal in unit voxel, and calculate the fat content distribution map; traverse the entire scanning field in units of pixels, and according to the results of the fat content distribution map, use FF≥20% as the threshold to distinguish the fat tissue area (FF>20%) and the tissue area dominated by water signal (FF<20%).

[0063] S23, perform different main magnetic field inhomogeneity correction processing on the fat tissue area and the tissue area dominated by water signal (such as Figure 3 shown).

[0064] Among them, for the fat tissue area, the highest peak and the second highest peak of the signal contained in the original Z spectrum are first extracted, and the order of appearance of the highest peak and the second highest peak is confirmed according to the principle of gradually decreasing relative water proton frequency offset from left to right (that is, the X-axis of the Z spectrum is marked from +10.0 to -10.0ppm from left to right), and the signal peak closer to the left of the X-axis of the Z spectrum is marked as water peak W, and the signal peak closer to the right of the X-axis of the Z spectrum is marked as fat signal peak F. Then, the Z spectrum main magnetic field inhomogeneity correction is performed based on the relative water proton frequency offset a where the fat signal peak F is located, and all relative water proton frequency offsets in the original Z spectrum are corrected by an offset of -a-3.4, and the Z spectrum after the main magnetic field inhomogeneity correction can be obtained.

[0065] Correspondingly, for the tissue area dominated by water signal, the maximum signal peak contained in the original Z spectrum is extracted, and the maximum signal peak is the water signal peak W. The relative water proton frequency offset b where the water signal peak W is located is set as the inhomogeneity offset of the main magnetic field, and all relative water proton frequency offsets in the original Z spectrum are corrected by an offset of -b, so that the Z spectrum after the main magnetic field inhomogeneity correction can be obtained.

[0066] S3, image reconstruction, specifically:

[0067] The water signal W, fat signal F, and asymmetric macromolecular proton signal obtained by the first three-cell Lorentz curve fitting are recorded. The water signal W, fat signal F, and asymmetric macromolecular proton signal mentioned above are subtracted from the Z spectrum corrected for the main magnetic field inhomogeneity to obtain the residual Z spectrum (e.g. Figure 4 The remaining Z spectrum was fitted with a second two-pool Lorentz curve (as shown in Figure 4 The creatine signal and amide proton transfer signal contained in the remaining Z spectrum are fitted. The superposition results of the first and second segmented two-step Lorentz curve fitting are shown as follows: Figure 5 As shown, the creatine signal was used as an imaging indicator to quantify the level of brown fat activity.

[0068] The two-pool Lorentz curve fitting model is:

[0069]

[0070] Among them, j = 1 is the creatine signal pool, j = 2 is the amide proton transfer signal pool; Z (ω) is the two L j (ω) The entire Z spectrum formed after superposition; L j(ω) is a signal peak with a peak value of A, a center frequency offset of ω0, a frequency offset of ω, and a peak half-width of lω.

[0071] In a specific application example, the cold exposure test condition is to apply a medical cold pack (6-10°C) to the shoulder and neck for 2 hours at a room temperature of 16-17°C, and avoid strenuous exercise during the period. The experimental process is as follows: Figure 6 As shown. The chemical exchange saturation transfer imaging data of the brown fat tissue of the shoulders and necks of healthy volunteers were collected before and after cold exposure to observe the effect of cold exposure on the activity of brown fat in the shoulders and necks of human bodies. The contrast of the obtained creatine signal corresponds to the activity of brown fat in the shoulders and necks of human bodies. The results show that after cold exposure, the creatine content of the volunteers' brown fat tissue increased significantly, as shown in Figure 2. Figure 7 , Figure 8 As shown, it is suggested that the magnetic resonance brown fat activity imaging method of the present invention can quantify the activity changes of brown fat in vivo.

[0072] The magnetic resonance brown fat activity imaging method of this embodiment provides a new method for quantitative imaging of brown fat activity. 18 F-FDG PET / CT imaging technology. The method described in this invention is non-invasive and radiation-free, low-cost, can be used in women and children, and is suitable for large cohorts and repeated observational studies.

[0073] It should be noted that, for the sake of convenience, the aforementioned method embodiments are all expressed as a series of action combinations, but those skilled in the art should know that the present invention is not limited to the described order of actions, because according to the present invention, certain steps can be performed in other orders or simultaneously.

[0074] Based on the same concept as the magnetic resonance brown fat activity imaging method in the above embodiment, the present invention also provides a magnetic resonance brown fat activity imaging system, which can be used to perform the above magnetic resonance brown fat activity imaging method. For ease of explanation, the structural schematic diagram of the magnetic resonance brown fat activity imaging system embodiment only shows the parts related to the embodiment of the present invention. Those skilled in the art can understand that the illustrated structure does not constitute a limitation of the device, and may include more or fewer components than shown in the diagram, or combine certain components, or arrange the components differently.

[0075] See also Fig. 9 In another embodiment of the present application, a magnetic resonance brown fat activity imaging system 100 is provided, the system comprising an image acquisition module 101, a main magnetic field inhomogeneity correction module 102 and an image reconstruction module 103;

[0076] The image acquisition module 101 is used to acquire chemical exchange saturation transfer images of the shoulder and neck area of ​​the human body;

[0077] The main magnetic field inhomogeneity correction module 102 is used to normalize the collected chemical exchange saturation transfer image to obtain an original Z spectrum image, perform a primary three-pool Lorentz curve fitting on the original Z spectrum image to find the location of the water peak, and correct the main magnetic field inhomogeneity of the original Z spectrum image;

[0078] The image reconstruction module 103 is used to perform two-pool Lorentz curve fitting again on the Z spectrum image after the main magnetic field inhomogeneity correction, and extract the creatine signal contained in the Z spectrum image. The creatine signal is used as an image quantification index reflecting the activity level of brown fat to achieve brown fat activity imaging.

[0079] It should be noted that the magnetic resonance brown fat activity imaging system of the present invention corresponds one-to-one to the magnetic resonance brown fat activity imaging method of the present invention. The technical features and beneficial effects described in the embodiment of the above-mentioned magnetic resonance brown fat activity imaging method are applicable to the embodiment of magnetic resonance brown fat activity imaging. For specific contents, please refer to the description in the embodiment of the method of the present invention, which will not be repeated here. This is hereby declared.

[0080] In addition, in the implementation of the magnetic resonance brown fat activity imaging system of the above embodiment, the logical division of each program module is only an example. In actual application, the above functions can be assigned to different program modules as needed, for example, for the configuration requirements of the corresponding hardware or the convenience of software implementation. That is, the internal structure of the magnetic resonance brown fat activity imaging system is divided into different program modules to complete all or part of the functions described above.

[0081] See also Fig.10 In one embodiment, an electronic device for implementing a magnetic resonance brown fat activity imaging method is provided. The electronic device 200 may include a first processor 201, a first memory 202 and a bus, and may also include a computer program stored in the first memory 202 and executable on the first processor 201, such as a magnetic resonance brown fat activity imaging program 203.

[0082] The first memory 202 includes at least one type of readable storage medium, and the readable storage medium includes flash memory, mobile hard disk, multimedia card, card-type memory (e.g., SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. In some embodiments, the first memory 202 may be an internal storage unit of the electronic device 200, such as a mobile hard disk of the electronic device 200. In other embodiments, the first memory 202 may also be an external storage device of the electronic device 200, such as a plug-in mobile hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card, etc. equipped on the electronic device 200. Further, the first memory 202 may also include both an internal storage unit of the electronic device 200 and an external storage device. The first memory 202 may not only be used to store application software and various data installed in the electronic device 200, such as the code of the magnetic resonance brown fat activity imaging program 203, but also be used to temporarily store data that has been output or is to be output.

[0083] In some embodiments, the first processor 201 may be composed of an integrated circuit, for example, a single packaged integrated circuit, or a plurality of packaged integrated circuits with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and combinations of various control chips, etc. The first processor 201 is the control core (Control Unit) of the electronic device, and uses various interfaces and lines to connect various components of the entire electronic device, and executes various functions and processes data of the electronic device 200 by running or executing programs or modules stored in the first memory 202, and calling data stored in the first memory 202.

[0084] Fig.10 Only an electronic device with components is shown, and those skilled in the art will understand that Fig.10 The structure shown does not constitute a limitation on the electronic device 200 , and may include fewer or more components than shown in the figure, or combine certain components, or arrange the components differently.

[0085] The magnetic resonance brown fat activity imaging program 203 stored in the first memory 202 of the electronic device 200 is a combination of multiple instructions, and when executed in the first processor 201, it can achieve:

[0086] Collect chemical exchange saturation transfer images of the human shoulder and neck area;

[0087] The collected chemical exchange saturation transfer image is normalized to obtain the original Z spectrum image, and the original Z spectrum image is subjected to the initial three-pool Lorentz curve fitting to find the location of the water peak and correct the main magnetic field inhomogeneity of the original Z spectrum image;

[0088] The Z spectrum image after the main magnetic field inhomogeneity correction is subjected to two-pool Lorentz curve fitting again to extract the creatine signal contained in the Z spectrum image. The creatine signal is used as an image quantification index reflecting the brown fat activity level to achieve brown fat activity imaging.

[0089] Furthermore, if the module / unit integrated in the electronic device 200 is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium. The computer-readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0090] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0091] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0092] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. Magnetic resonance imaging of brown fat activity, It is characterized in that The steps include: Collect chemical exchange saturation transfer images of the human shoulder and neck area; The collected chemical exchange saturation transfer image is normalized to obtain the original Z spectrum image, and the original Z spectrum image is subjected to the initial three-pool Lorentz curve fitting to find the location of the water peak and correct the main magnetic field inhomogeneity of the original Z spectrum image; The Z spectrum image after the main magnetic field inhomogeneity correction is subjected to two-pool Lorentz curve fitting again to extract the creatine signal contained in the Z spectrum image. The creatine signal is used as an image quantification index reflecting the brown fat activity level to achieve brown fat activity imaging.

2. The magnetic resonance brown fat activity imaging method according to claim 1, It is characterized in that The step of collecting the chemical exchange saturation transfer image of the human shoulder and neck region is specifically as follows: A chemical exchange saturation transfer magnetic resonance sequence was used to acquire multiple radio frequency pulse saturation images at different frequency offsets relative to water protons in a magnetic resonance imaging system. z and an additional unsaturated reference image M 0 .

3. The magnetic resonance brown fat activity imaging method according to claim 2, It is characterized in that The relative water proton resonance frequency shift range of the collected chemical exchange saturation transfer image is from -10ppm to +10ppm, which must include -3.5ppm, 0ppm, +2.0ppm and +3.5ppm saturation images, plus a non-saturated image with a frequency shift of +300ppm.

4. The magnetic resonance brown fat activity imaging method according to claim 2, It is characterized in that The relative water proton frequency offsets of the chemical exchange saturation transfer image collected by the Z spectrum are: +300ppm, ±10ppm, ±8ppm, ±6ppm, ±5.75ppm, ±5.5ppm, ±5.25ppm, ±5ppm, ±4.75ppm, ±4.5ppm, ±4.25ppm, ±4.0ppm, ±3.75ppm, ±3.5ppm, ±3.25ppm, ±3.0ppm, ±2.75ppm, ±2.5ppm, ±2.25ppm, ±2.0ppm, ±1.75ppm, ±1.5ppm, ±1.25ppm, ±1.0ppm, ±0.75ppm, ±0.5ppm, ±0.25ppm, and 0ppm.

5. The magnetic resonance brown fat activity imaging method according to claim 1, It is characterized in that The correction of the main magnetic field inhomogeneity of the original Z spectrum image is specifically as follows: Multiple radio frequency pulse saturation images M at different frequency offsets in the collected chemical exchange saturation transfer images z For the non-saturated reference image M 0 Perform normalization processing to obtain the original Z spectrum image; The original Z spectrum image is fitted with the first three-pool Lorentz curve to fit the direct saturated water pool, methylene fat pool and asymmetric macromolecular proton pool contained therein; The extracted direct saturated water signal W and methylene fat signal F are calculated according to the formula Where W and F are the peak values ​​of the extracted water and fat signals, respectively. The proportion of fat signal in the water and fat signals in a unit voxel is calculated, and the fat content distribution map is calculated. The entire scanning field is traversed in units of pixels, and according to the results of the fat content distribution map and the set threshold, the fat tissue area and the tissue area dominated by the water signal are distinguished. Different main magnetic field inhomogeneity correction processes are performed on the fat tissue area and the tissue area dominated by water signals; Among them, for the fat tissue area, the highest peak and the second highest peak of the signal contained in the original Z spectrum image are first extracted, and the order of appearance of the highest peak and the second highest peak is confirmed according to the principle of gradually decreasing relative water proton frequency offset from left to right, and the signal peak closer to the left of the Z spectrum X-axis is marked as water peak W, and the signal peak closer to the right of the Z spectrum X-axis is marked as fat signal peak F; then, the main magnetic field inhomogeneity correction of the Z spectrum image is performed based on the relative water proton frequency offset a where the fat signal peak F is located, and all relative water proton frequency offsets in the original Z spectrum are corrected by an offset of -a-3.4 to obtain the Z spectrum after the main magnetic field inhomogeneity correction; For tissue areas dominated by water signals, the maximum signal peak contained in the original Z spectrum is extracted, and the maximum signal peak is the water signal peak W; the relative water proton frequency offset b where the water signal peak W is located is set as the inhomogeneity offset of the main magnetic field, and all relative water proton frequency offsets in the original Z spectrum image are corrected by an offset of -b to obtain a Z spectrum image after the main magnetic field inhomogeneity correction.

6. The method for magnetic resonance brown fat activity imaging according to claim 5, It is characterized in that The model used for the three-pool Lorentz curve fitting is as follows: Among them, i = 1 is the direct saturated water pool, i = 2 is the methylene fat pool, i = 3 is the asymmetric macromolecular proton pool, and Z(ω) For multiple L i (ω) The entire Z spectrum formed after superposition; L i (ω) has a peak value of A and a center frequency offset of ω 0 , a signal peak with a frequency offset of ω and a peak half-width of lω.

7. The magnetic resonance brown fat activity imaging method according to claim 1, It is characterized in that The Z spectrum image after the main magnetic field inhomogeneity correction is subjected to two-pool Lorentz curve fitting again to extract the creatine signal contained in the Z spectrum image, specifically: Record the water signal W, fat signal F and asymmetric macromolecular proton signal obtained by the first three-pool Lorentz curve fitting; subtract the water signal W, fat signal F and asymmetric macromolecular proton signal mentioned above from the Z spectrum image after the main magnetic field inhomogeneity correction to obtain the residual Z spectrum image; Performing a second two-pool Lorentz curve fitting on the remaining Z spectrum image to fit the creatine signal and amide proton transfer signal contained in the remaining Z spectrum image; wherein the creatine signal is used as an imaging indicator for quantifying the activity level of brown fat; The model used for the two-pool Lorentz curve fitting is: Among them, j = 1 is the creatine signal pool, j = 2 is the amide proton transfer signal pool; Z (ω) is the two L j (ω) The entire Z spectrum formed after superposition; L j (ω) has a peak value of A and a center frequency offset of ω 0 , a signal peak with a frequency offset of ω and a peak half-width of lω.

8. Magnetic resonance brown fat activity imaging system, It is characterized in that A magnetic resonance brown fat activity imaging method applied to any one of claims 1-7, comprising an image acquisition module, a main magnetic field inhomogeneity correction module and an image reconstruction module; The image acquisition module is used to acquire chemical exchange saturation transfer images of the shoulder and neck area of ​​the human body; The main magnetic field inhomogeneity correction module is used to normalize the collected chemical exchange saturation transfer image to obtain an original Z spectrum image, perform a first three-pool Lorentz curve fitting on the original Z spectrum image, find the location of the water peak, and correct the main magnetic field inhomogeneity of the original Z spectrum image; The image reconstruction module is used to perform two-pool Lorentz curve fitting again on the Z spectrum image after the main magnetic field inhomogeneity correction, and extract the creatine signal contained in the Z spectrum image. The creatine signal is used as an image quantification index reflecting the brown fat activity level to achieve brown fat activity imaging.

9. An electronic device, It is characterized in that The electronic device comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores computer program instructions that can be executed by the at least one processor, and the computer program instructions are executed by the at least one processor so that the at least one processor can perform the magnetic resonance brown fat activity imaging method as described in any one of claims 1-7.

10. A computer-readable storage medium storing a program, It is characterized in that When the program is executed by a processor, the magnetic resonance brown fat activity imaging method according to any one of claims 1 to 7 is implemented.

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